Automatic telephone system.



A. ANDERSEN. AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILED JUNE 7. l9l6.

ma ma Patvnfvd 5mm 11., 1918- 2 SHtETS-SHEET l- W/TA/[JSKS A ANDERSEN AUTOMATIC TLEPHON SYSTEM.

APPLICATION FILED JUNE 1| 916- LQEQ Q%5 Jia'tmntedJunc 11. 1918.

2 SHEETS SHEET 2.

I To all whom it may concern:

nrr sans Ienn rennin.

. ALBERT ANDERSEN, OIE CHICAGO, ILLINOIS, ASSIGNOR T AUTOMATlG ELECTRIC conrrnn'r, or CHICAGO,

AUTOMATIC TELEPHONE SYSTEM.

messes.

Be it known that I, 'ALBERT Annnnsnn, a

citizen of the United States of America, and

a resident of Chicago, 'county of Cook, and State of Illinois, have invented certain new and useful Improvements in Automatic 1 Telephone Systems,

of which the following is a specification.

My invention relates in general to automatic telephone systems, but is particularlyconcerned with employ meters devices in connection with the individual subscribers stations. system in common the exchange for such automatic systems as use. employs a meter at each subscr1bers. llne,

which is operated when the associated line is callip by the. reversal .of current in the line when the called subscriber answers.

In systems of the foregoing character there are usually a number of telephones, such for example, as the telephones at fire or police headquarters, or those assigned to ofiiciails of the telephone company, ,to which it is desired that all subscribers should have free access without being charged. In the past it has been customary to place all the free telephones in one group and so arrange the connector switches serving that group that they will not, reverse the current in calling'lines. This plan is open to the objection of inefliciency, for the free telephones are usually very few, or at least are generally considerably less in number than the capacity of a connector switch. It is desirable, therefore, to provide a connector switch capable of serving both kinds of telephones the' ordinary subscribers stations,

connections to-which are charged for, and .the special telephones to which free access Specification of Letters Patent.

or other measured-service,

A measured servicetially the receiver 2,

substation A is of 1906; being,

' particular type disclosed in the British pat- ILLINOIS, A CORPORATION 015 ILLINQIS. i

Patented June 11, 101%.

Application filed June 7, 1916. Serial No. 102,131.

plained and described hereinafter, reference-being had to the accompanying drawangs, which show diagrammatically a comswitching equipment used in setting up the complete connection shown comprises the individual line switch C, theselector switch E, and the connector switch F.

Referring now to Fi A may be of any suitab tion such, for example, as the type disclosed in British patent to T. G. Martin, #1419 of 1910. As shown herein it comprises essentransmitter 3, switch hook 4:, ringer 5 andcondenser 6. Being an automatic substation there is also provided a pair of impulse springs 7 and 8 controlled by the impulse wheel 9 through the medium of a finger hole dial (not shown).

The line conductors 12 and 13 of the sub station A are connected at the exchange to the individual line switch G whichmay be of the general type of line switch disclosed in British patent to R. W. James, #26301 of 1906; being, however, of the particular type shown in United States Letters Patent #1,078,690, granted Jan; 17, 1912, to Frank Newforth. Since line switches of the above type are well known and form no part of my invention an extended description will not be given. It will suffice to say that through the medium of line switch C the e type or construc- -line of substation A, when calling, is given access ma plurality of selector switches, one of which is shown at the right of Fig. 1 and is indicated by reference character E. Being a measured service substation, the

also provided at the exchange with a meter M, which as shown herein is similar to the reverse current controlled meter shown and described in the. British patent to the Automatic Telephone Mfg. (30., #29354 of 1912.

,The master switch D is of the general type of master switch mentioned British patent to James, #2630]. however, more nearly of the en to Martin, #1419 of 1910. As is well understood, the function of the master 1, the substation disclosed in the above called number to select one of a number of switch is to maintain the plungers of all idle line switches in position before the terminals of an idle trunk line.

The selector switch E is of the general type of selector switch disclosed-in U. S. Letters Patent #815,321, granted March 13, 1906, to Keith, Erickson, and Erickson, being, however, of the particular type disclosed in British patent to the Automatic Telephone Mfg. (30., #2513015 1914. Such a selector switch, as is well known, may be operated. in response to the first digit of 1.

groups into which the subscribers lines terminating in the exchange are divided. For this purpose the selector E may be given accessto a number of groups of trunk lines, the trunk lines of each group being extended to a group of connector switches. I One of these trunk lines is shown as ex tending to the connector F (Fig. 2), which may be of the general type of connector switch disclosed in U. S. Letters Patent #815,176, granted March 13, 1906, to Keith, Erickson, and Erickson; being, however, of the particular type disclosed in U. S. Letters Patent #123,901, reissued April 13, 1915, to

Frank Newforth. A connector switch of the foregoing type may be given access to a group of one'hundrcd subscribers lines and is operable in response to the two last digits of a called number to establish connection with any line in the group. As before mentioned, in accordance with my invention the lines accessible to the group of connectors of which connector F is one may be of two kinds, viza, lines to which connections may be made tree of charge and the ordinary subscribers lines, for connections to which a charge is made. The lines of the latter type have their terminals.- arranged in the connector banks in rows or levels in the usual manner, being restricted, however, to the first nine levels. The upper or tenth level is reserved for the special tree service lines. lnasmueh as the special lines all have their tGllTllIltllS located in the tenth level of the connector banks. it only remains to provide means in each connector switch whereby when connection is completed to a line in that level, the reversal of current in the calling line will be prevented. 'llhisincans as shown in the connector F (Fig. 2) comprises the shaft controlled springs S which are operated by the cam 15-10 when the switch shaft reaches its extreme upward position. The effect oi the operation of the springs S will appear more clearly in the description of the operation which is to follow.

The substation A and the associated individual line switch C maybe similar, rcspectively, to the substation A. and the line switch C which have already been briefly described. As shown in Fig. 2 the substation A is not provided with a meter, for it will usually be the case that where no charge is made for incoming calls, the outgoing calls will not be charged for either; 11 meter similar to the meter M (Fig. 1) may be provided, however, if so desired.

Forthe purpose of supplying current for operating and talking purposes I have shown a battery 13 having its positive pole grounded. The auxiliary apparatus comprising the ringing current generator R, the ringing interrupter 1, and the busy signaling machine Q are of the ordinary type and perform the same functions as the same named pieces of apparatus in other automatic exchanges.

Having given a brief description of the apparatus, 1 will now proceed to an explanation of the operation of. the same. Inasmuch as the automatic equipment shown herein, excepting a certain modification of the connector F, is well known in the art, having been fully described in the publications above referred to, the operation will be described in a more or less general manner.

When the calling subscriber at substaf tion A removes his receiver to initiate the call an energizing circuit is completed over the line conductors 12 and 13 for the line relay 14: of the line switch C. Upon attracting its armature, the line relay 14: closes a circuit for the pull-in Winding 18. Upon energizing. the pull-in winding operates both the plunger arm 15 and the cutofi armature 16; the former through the me the bank springs 30-33, inclusive, into en gagemcnt, respectively, with contacts 34:37, inclusive, and the latter disconnecting the line conductors 12 and 13, respectively, from the line relay 1% and from ground. By the engagement of bank springs 30'aiid with contacts 3% and 37, rcspcctivel y, the line, conductors 13 and 12 are extended through normally closed contacts of the switching relay 63 to the double wound line relay 60 of the selector E.

The line relay (30 is accordingly energized over the loop circuit including substation A and. upon attracting its armature, closes a circuit for the slow-acting release relay 51. Upon energizing. the release relay closes a holding circuit for the line switch (3 which may be traced from grouud'G by way of contact springs (35, contact 3:). bank spring 31 and the holding winding 17 to battery it. Since the line relay 14 is slow-acting, it retains lLS armature to maintain the pull-in winding [8 energized until after the above holding circuit has been established. A branch of the holding circuit extends by way oi conductor 20 to multiple test contacts in the banks of connector switches having access to the lineof substation A.

where by a ground potential on these test w netizing effects are in opposition, wherefore contacts the said line is made busy. A second branch of'the holding circuit extends by way of the right hand winding of the meter magnet 21 and the contact springs 19 (now closed by the plunger arm to-the battery B. conductor 13,

It will be observed that line as extended to the line relay 60, includes the left hand winding of meter magnet-21. The two windings are so connected, however, that at this time their magthe meter is not operated. It should be mensition before the te tion'ed, also that neither winding of the meter magnet is suliiciently powerfulto operate it alone.

By the engagement of bank spring 32 with contact 36 a circuit is closed whereby the master switch D is operated in the Well known manner to advance the plungers of 20 moval of the receiver at substation A. The

I circuit calling subscriber may now manipulate his dial in accordance with the first digit of the desired number, thereby separating momentarily the impulse springs 7 and 8 a number of times and interrupting each time the circuit of line relay of selector E. As a. re sult of these line relay'GO is deenergized a corresponding number of times, sending an impulse at from ground at G te the slow-acting relay 62 and the vertical magnet 65 in series. The vertical magnet in response to thesr pulses, steps up the switch shaft until the wipers 70, 71, and 72 stand opposite the her zontal level in which are located contactswhich are terminals of the desired group of trunk lines. The relay 62, being slow-acting retains its armature during for the test relay 64, which latter relay prepares a circuit for the rotary magnet'66 andlocks itself to ground at G At the end of the series of impulses the relay -.62 denergizes, thereby completing the aforementioned circuitof the rotary magnet 66,

whereupon the wipers 70, 71, and 72 start rotating in 'searchof an idle trunk line. As

is well known, the rotary magnet interrupts its own circuit and also the locking circuit of'the test relay at every energization, the

' contacts in the latter circuit, howeveiybeing short-circuited by to 7 thetest or private wiper 1' while passing over grounded busy con- 1 tacts; As soon, therefore, as the test wiper '71 arrives at an ungrounded test contact'the test relay 61 deiinergizes and opens the rotary magnet circuit. thereby'bringing the wlpers to rest upon the terminals of an idle minals of the next idle interruptions of its circuit the the series of impulses and closes a.v

igaeaaee trunk line, assumed to be in this case the contacts 73, 74, and '75. As a further result of the deenergization of the test relay 54;, a circuit is completed for the line switchmg relay 68 which relay, upon energizing,

disconnects the extended line conductors 13 The line relay 100 thereupon energizes.

over the line circuit extending back through substation A and completes an energizing circuit for the slow-acting relay 101. Relay 101, vupon attracting its armature, prepares a circuit for the vertical and rotary magnets 104 and 105 andalso completes a new holding circuit as follows: ground at G, contact springs 119, bank contact 74 and wiper 71 to wire junction 80, where the circuit divides, one branch extending by way of a back contact of relay 64 through the winding of line switching relay 63 to battery'B, and the'other branch extending by way of ofi'-normal contact 67 and inter rupter contact 81 to wire junction 82 where it joins the previously described holding circuit extending back to the line switch C.

The subscriber at substation A may now operate his dial in accordance with the second digit of the desired number, assumed in'this case to be the digit 0, resulting in deenergizations of the line relay of the connector F. At each de'energization, the line relay 100 sendsan impulse from ground at G to the slow-actingrelay 107 and the Vertical magnet 104 in series, side switch wiper being in its first position. The vertical magnet, in response to these impulses, steps up the shaft until the wipers :120, 121, and 122 stand opposite the tenth horizontal level of bank contacts, this being the level in which the line of substation A terminates. Relay 107, being slow-acting, retains its armature during the series of impulses and maintains a circuit from ground at G for the private magnet 10S and the wiper cut-off relay 111 in parallel. At the end of the series of impulses, the relay 107 deenergizes and breaks the circuit of the private magnet, which latter controls the side switch wipers in the usual manner to advance them 'to-their second position.

The subscriber at substation A may now operate his dial in accordance with the third and final digit of the desired number, resulting as before in deenergizations of the line relay 100.

Now, however, side switch wiper 115 being in its second position, the line relaysends impulses to the slow-acting relay 107 in series with the rotary magnet 105.

The rotary magnet operates in response to I bank con. lets 123, 124, and 125, these contacts forming the terminal of the line of substation A in the bank of connector F. The private magnet 108 and the wiper cutoff relay 111 are energized during the last series of impulses as before, the latter disconnecting the line wipers during rotation and the former, upon deenergizing, controlling the side switch wipers to advance them to their third position, it being assumed that the line of substation of A was idle when called.

As side switch wiper 114 comes into engagement with its third'position contact point a circuit is completed for the holding winding 17 of line switch C as follows: round at G, side switch wiper ll-l (in third position), wiper 121, bank contact 124:, and holding winding 17 to battery B. By the attraction of the cut-oft armature the line conductors 12 and 13 are disconnected, respectively, from ground and from the line relay 1 1-. The holding winding 17 is not sulliciently powerful to operate the plunger arm 15 of the line switch C. Ground at G also extends to multiples of bank contact 121 in the banlns of other connector-s of the group, thereby making the line of sub station A busy to other calls.

By the engagement of side switch wipers 112 and 113 with their third position contact points the connection between the calling and the called substations is completed, relay 111 being denergized. By the engz gement of side switch wiper 115 with its third position contact point, a circuit is completed for the ringing relay 109 in series with the interrupter 1, whereby ringing current is projected intermittently out over the line of substation A to operate the signal in bridge thereof.

The subscriber at substation A has now established the required connection with substation A and the bell at the latter substation is being rung to attract the atten tion of the called subscriber. Before proceeding further it will be well to consider the comlition ot the shaft controlled springs 3. When the connector F was operated in response to the second digit 0 ol the called number the. shaft was raised to the ulDcrmost or tenth level as described. At the last step, by means of a suitable cam 130 carried on the shaft the springs S are shifted to the position shown in the drawing. The springs S, as regards their wiring connections, are associated with the usual line re versing springs of the back bridge relay 102, and are so connected that when operated the said back bridge relay will not be effective to-reverse the incoming lines upon the response of the called subscriber.

To proceed with the operation, when the called subscriber removes his receiveriron the hook a circuit is completel for the double wound back bridge relay 1 2 inthe well known manner. Upon attracting its armature, the relay 102 closes a circuit for the ring cut-ofl' relay 110 which relay locks itself to ground at G and also opens the circuit of the ringing relay 109, thereby stopping the ringing operation. The back bridge relay also shitts its line reversing springs which operation would ordinarily result in the reversal of the incoming line conductors as regards their connections to the windings.

of the line relay 100. Now, however, since the shaft controlled springs S have been operated, the operation of the back bridge line reversing springs is of no efl'e'ct and the current in the called line continues to flow in the same direction as"before. It follows that the meter M will not be operated.

The calling and called subscribers may now converse without further'cftort. Current for the transmitter at substation A. is supplied through the windings'of the line relay 100, while current for the transmitter at substation A is supplied through the windings of the back bridge relay 102. The voice currents follow the path shown in the heavy lines which, it is thought, will be ap parent without further amplifying the enplanation. It may be mentioned however, that the left hand winding of the meter magnet 21 is bridged by a small condenser in order to provide a good talking circuitwhen the meter is not operated.

When the conversation is completed both subscribers will hang up their receivers. By the replacement of the receiver at sub- 'station A the circuityof the line relay 100 of the connector F is broken. Upon do energizing, relay breaks the circuit of slow-acting relay 101. Upon the denergization of relay 101, the connector F is restored to normal in the regular manner through the medium of the release magnet 103, and as a further reslilt ground is re moved from the holding trunk extending back to selector E ,and the line switch C. By the removal of ground from theholding trunk, relay 63 of the selector 1*] is dei nergized, whereby the selector E is restored to normal in the usual manner thro'u 'h the medium of release magnet 69. As a} turther result of the removal of ground from the holding trunk, the holding winding 17 of the line switch C is decnergizcth-thereby allowing the plunger to-be withdrawn from the bank and restoring the line switch to its normal position.

The operation of a connector switch such as the connector F when connection is at tempted with a busy line is well known and has been described in the publications previouslv mentioned. My invention involves nothing new in connection with this feature,

consequently it is thought to be unnecessary to describe such operation here.

If tliecalled line had been an ordinary subscribers line provided with multiple terminals in one of the lower levels of the connector F, the shaft controlled springs S would not have been shifted when the connector F was operated; for, as has been explained, the said springs are shifted only when the connector shaft is raised to the tenth level. It is evident that upon the response of the called subscriber in this latter case the back bridge relay 102 would be eltective to reverse'the incoming line conductors as regards their connections to the windings of the line relay 100. The direction of current flow in the calling line is accordingly reversed to operate the meter M in the usual manner through the cooperation of its two windings.

It will be seen from the foregoing that I have devised a simple and eflicient connector switch capable of serving telephone lines of two classes. and able to discriminate between the lines of different classes in order to charge for connections to lines of one class while not charging for connections to lines of the other class.

\Vhilei I have found it convenient in ex plaining my inventionto show and describe a certain specific embodiment thereof, I consider it probable that the invention may be modified to suit other conditions or to adapt it to other types of apparatus without the exercise of any talent beyond ordinary mechanical ingenuity. For example, by means of a' suitably designed cam 130, the springs S may be shifted at any other level instead of the tenth level, or, if de sired, they may be shifted when connection is established to any one of a plurality of levels. In case connectors other than those of the vertical and rotary type are to be used the springs S may be so arranged that they will be shifted at any desired point in the travel of the movable contact carrying mechanism, the particular; arrangement in each case depending on the mechanical construction of the connector to which the-invention is being'adapted.

In view of these considerations I do not wish to limit myself'to the exact construction shown herein but desire to inplude and v have protected by Letters Patent ,all moditications of my invention which may here after bc-deviscd, limited only by [the scope of the appended claims.

What I claim as my invention is:

1. In a telephone system, a calling line provided with a toll assessing device, a plurality of other lines of two kinds, means for connecting the calling line with a called one of said other lines, automatic means for operating said device .to re ister the call, and automatic means common to all of said all of said other lines for lines for preventing the operation of said ldevce when the called line is of a particular 2. In a telephone system, a calling line provided with a toll assessing device, a pinrality of other lines of two kinds, means for connecting the calling line with a called one of said other lines, and controlling means for said device common to said other lines adapted to discriminate between the two kinds of lines whereby if the called line is of one kind the device is operated and if the called line is of the other kind the device is not operated.

3. In a telephone system, the combination with a calling line provided with a measured service device, a plurality of other lines, and means for connecting said calling line'with any one of said other lines, of means for operating said device to register the call, and automatic means common to preventing the operation of said device whereby certain of said other lines may be rendered accessible free of charge.

4:. In a telephone system, an automatic conn ctor switch, lines of two kinds acces sible to said switch, a calling line and means for extending it to said switch, a toll assessing device for said calling line, means for operating said switch to connect with any one. of said first lines, means for operating. said device if connection is established with a line of one kind, and means individual to said switch for preventing the operation of said device if connection is established with a line of the other kind.

5. In a telephone system, a calling line provided with a registering device, a connector switch, a plurality of other lines accessible to said switch, means for extending the callingline to said switch, means "For operating said switch to connect with any one of said other lines, means for operating said register when the called subscriber answers, and means common to said other lines for rendering said last means inetiective when a particular line is called.

6. In a telephone system, a calling line provided with a toll assessing device, a connector switch, a plurality of other lines divided into groups and accessible to said switch, means for extending the calling line to said switch, means for operating said switch to connect with any one of said other lines, means for operating said device when the called subscriber answers, and means common to said othcrlincs for rendering said last means incll'ectivc when a line in a articular group is called.

In a telephone system, a plurality of lines of two kinds, a calling line provided with a measured service device, a two motion connector switch and means for extending the-calling line thereto, means for operating said switch to connect with any one of said lines, the kind of line connected with being dependent on the extent of the first movement of said switch, means for operating said device to register the call, and means in said switch for preventing the operation of said device it the first movement of said switch extends beyond a predetermined limit.

8. In a telephone system, a plurality oi lines of two kinds, a calling line provided with a measurec service device, a connector switch and n'ieans for extending the calling line thereto, means for operating said switch with a vertical and rotary motion to connect with any one of said lines, the kind oil line connected with being determined by the vertical movement of said switch, means for operating said device to register the call, and means controlled in the said vertical movement of the switch to prevent the operation of said device if a line of a particu lar kind is called.

9. In a telephone system, a plurality of lines of two kinds provided with fixed ter- Ininals arranged in rows or levels, the lines of each kind being arranged in separate levels. an automatic connector switch pro- 'vided with movable terminals, a calling line and means for extending the same to said switch, means for operating said switch to connect with any of said first lines through the medium of said fixed and movable terminals, a measured service device for the calling line, means for operating said device to register the call, "and means individual to said connector switch for rendering said last means ineffective if the called line has its terminals located in a particular level.

10. In a telephone system, an automatic connector switch, a line terminating, in said switch, a source of current for said line, means for transmitting series of current impulses over said line to operate said switch, a relay in said switch to reverse the current in said line, a device responsive to such reversal, and means individual to said switch for preventing such reversal when said switch is operated in response to a particular series of impulses.

11. In atelephone system, the combina tion with a calling line and a reverse current controlled measured service device therefor, of a called line, means including a connector switch for connecting the two lines,

a source of current for talking purposes, means for reversing the flow of current in the calling line to operate said device, and means individual to said switch for preventing such reversal oi current when connection is established. with the said called line.

Signed by me at Chicago, Cock county, State of Illinois, this 1st day of June, 1916,

ALBERT ANDERSEN. 

